This invention relates to instrumentation and analysis systems for use in holes within the earth, and, more particularly, to instrumentation and analysis systems for non-sliding and accurate emplacement of instruments and fluids within underground holes.
Holes are made in the earth for any number of reasons, including, e.g., oil and gas production, accessing below ground nuclear explosion sites, geological monitoring, and the like. It is frequently required to obtain information along the hole walls with accurate relationship to the location within the hole, whether the hole is vertical or horizontal. The information may be obtained from instrumentation such as thermocouples, pressure sensors, fiber optic sensors, and the like. Also, samples of fluids and geological structure may be needed.
There are two significant problems associated with obtaining information along hole walls: hole integrity and specimen availability. First, holes may be placed in weak or unconsolidated geological materials that is subject to collapse, with concomitant loss of equipment and loss of the hole. In conventional systems, instruments are simply "dragged" in and out of the hole along the outside of drill stems, pipes, wire lines, and the like, such that contact with the hole wall can result in damage to the hole.
Another problem is that of obtaining pore fluid and geological samples from hole locations where there is no fluid or movement of the specimens to be obtained. For example, contaminants such as gasoline or solvents will flow through the unsaturated surface soils and rock to the water table under the force of gravity and capillary action. There is no actual flow into the hole from which fluid may be obtained. Other applications may also require the extraction of specimens from hole wall locations.
Many applications require that the location of the sample be accurately known for correlation with geological strata and elevations (or travel distance) within the hole. In conventional sampling, hole fluid and soil samples are subject to being wiped along the hole wall. This action tends to spread contaminants along the wall, as well as to pick up materials from different elevations. It is then difficult to have an accurate determination of the location from which the sample was obtained.
These problems are addressed by the present invention and an improved system is provided for placing instruments and sensing and sampling materials along a hole wall.
Accordingly, it is an object of the present invention to place instruments along a hole wall without significant damage to the hole wall.
It is another object of the present invention to obtain sample materials from a hole wall by relatively passive means even in the absence of any fluid flow or collection of fluids.
Yet another object is to place instruments and obtain samples at accurately known locations.
Still another object is to prevent the contamination of samples obtained from the hole wall.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.